"I grew up in Orlando, graduated from high school there, got married there and had four of my children there," Frazier said in a statement. "Last week, my heart was broken by a senseless tragedy. I wondered: What can we do? How can we help? This September, we're inviting our community of fans to come help us raise as much money as we can for the families that were impacted."

The celebrities will meet fans, take photos and sign autographs.

Frazier stressed that 100 percent of the profits -- from ticket sales, autographs, professional photo ops and vendor sales -- will be going to the OneOrlando Fund.

"From our actors and photograph vendor to our volunteers and the Orange County Convention Center, everyone involved has stepped up to make Fan Fest Orlando possible," said Jackie Prutsman, Orlando native and vice president of Fan Fest. "Our hometown needs us. We've always supported each other, regardless of race, orientation or creed, and this makes that all the more clear."